Arrangements for electrical switches



March 9, 1965 w. HOLZER ARRANGEMENTS FOR ELECTRICAL SWITCHES Filed May15. 1961 IVA/W /N VEN TOR WALTER HOLZER y/ A Horneys United StatesPatent 3,172,966 ARRANGEMENTS FOR ELECTRICAL SWITCHES Walter Holzer,Schutzenrain, Meershurg (Bodensee), Germany Filed May 15, 1961, Ser. No.109,902 Claims priority, application Germany, May 20, 1960, H 39,484 5Claims. (Cl. 200-17) This invention relates to an electromechanicalswitching apparatus.

The principal object of the invention is to provide an improvedconstruction of electric switches, that lends itself to use in anarrangement having a relatively large number of contacts to be operated.The construction is to be susceptible of compact arrangement andeificient operation, while being also capable of economic manufacture.

In the past, switch structures have been suggested, comprising contactcarriers disposed on cylindrical members, operated by a plurality of camsurfaces. These constructions have however been bulky and have notpermitted the use of as many contact arrangements as are likely to berequired in certain applications. For example, in automaticallyoperating washing machines it may arise that large number of contactarrangements are necessary and the present invention can be applied withadvantage to a switch for this duty.

Broadly, the present invention consists of an electric switch comprisingtwo adjacent and relatively movable members, the first of said membersbeing formed with cam surfaces, the second of said members carryingcontacts and contact operating means. A contact operating meanscomprises cam followers extending through openings in the said secondmember and engaging co-operating cam surfaces carried by the othermember. In the preferred construction in accordance with the inventiontwo insulating plate members are used, mounted for relative rotation,the two plates being pressed resiliently one against the other. Withsuch a construction, it is possible to provide a large number ofcontacts operated by means of the cams disposed in concentric grooves inone of the adjacent surfaces, and the contacts being operated by meansof simply formed parts, carried on the other member and having portions,providing cam followers, which extend through openings in the one memberand engage the cam surfaces. The openings in the one member can serve asguides and supports for the cam follower members.

This construction has the advantage that the danger of mechanical damageto the plates which are engaged by the freely disposed contacts isminimized. Also, the risk of voltage flash over is reduced. As guidesare provided for the contact movement, adjustment is simpler, and it isalso advantageous that all the contact making portions are on one faceof the plate, and remote from the side on which the camming operationtakes place. This is especially advantageous when a switch of this kindis used in the washing machine, as it improves the reliability of theswitch in circumstances where it may be subjected to moisture orvibration. Also, contact members are disposed on a flat plate, it ispossible for this plate to be manufactured as a printed circuit member.

In order to enable the larger number of contacts to be accommodated onthe switch, it is advantageous if the contact-operating members arearranged on edge, with the cam follower portions arranged in groups, andfor the groups to be disposed at dilferent angles for example at 90,with respect to each other around the plates. Also, if desired, thecontact operating members can be arranged radially on edge.

3,172,966 Patented Mar. 9, 1965 "ice It is convenient if the fixed andmoving plates are held together by means of a central spring, withinterposed spacing means, which permit the desired relative movement ofthe plates. An assembly of this kind is very simple. Spacing means canbe used which, while permitting the desired relative rotating orreciprocating movement of the plates, ensure a constant and predictabledistance between the adjacent faces of the plates, with constantreliability of operation.

The invention will be better understood from the following descriptionof embodiments thereof, in conjunction with the accompanying drawing, inwhich:

FIGURE 1 is a diagrammatic vertical section of a switch in accordancewith the invention;

FIGURE 2 is a plan view of a switch of FIGURE 1, and shows the line 11on which the section of FIGURE 1 is taken;

FIGURE 3 is a fragmentary section showing one of the insulating platesof the switch and an operating lever;

FIGURE 4 is a plan View of parts shown in FIGURE 3;

giGURE 5 is a detail view of a plug-type connector an FlGURE 6 is adiagram showing an alternative construction, with a differentarrangement of the operating levers.

The switch constructions which are shown in these drawings are suitablefor controlling the programme of operation of a fully automatic domesticappliance such as a washing machine or dish-washing machine. The switchshown in FIGURES l and 2 comprises two plates, a fixed plate 1 and amovable plate 2. Both plates are formed of insulating material,preferably by moulding a plastic material. The two plates are relativelymovable; in this example the plates are mounted for relative rotation,but alternatively can be arranged to slide one over the other in areciprocatory fashion. As shown, the two plates 1 and 2 are mounted upona common spindle 3 and are resiliently pressed towards each other bymeans of a compression spring 4 which can be arranged above, as shown,or below the fixed plate 1. Between the two plates are arranged spacingmeans indicated at 5, 6, to ensure uniform separation between theadjacent surfaces of the two plates. The spacing means can be formed,for example, as balls running in grooves formed in one or other of theadjacent faces, or they can be arranged as fixed spacers, which whereconsiderable pressure is imposed between the adjacent faces can be madeof material which is self-lubricating.

The moving plate 2 has a series of concentric grooves indicated at 7, inthe base of which are provided a series of cam surfaces. The camsurfaces are not shown in detail, but their position is indicateddiagrammatically at 8 in FIGURE 2. These cams co-operate with camfollowers of which one is shown at 9 in FIGURE 3, the cam followersbeing carried by actuating arms 11, the arms being held each by a rivetsuch as 17 to the plate 1. Each arm carries a moving contact 13, whichco-operates with a stationary contact 12 mounted on the plate 1. Inresponse to the cam follower moving over the cam projection, the barwill move vertically, in the direction indicated by arrow 1t), andthereby engagement of contacts of 12 and 13 is made and broken. Arrow1%) also denotes the axial direction of spindle 3. The cam followers 9extend through apertures arranged in the fixed insulating plate 1. Theapertures also act to guide the cam followers in their axial, verticalmovement.

Electrical connection can be made to the arms 11 by any suitable means,and one such means is indicated at 18, consisting of spring contactmembers which embrace the end of the bar and also the plate 1.

As shown in FIGURE 2, it is advantageous if the cam followers such as 9are arranged in groups, indicated at 19, 20, 21 and 22 which areradially arranged, and disposed at angles of 90 about the shaft 3. Aswill be apparent from FIGURE 2, the contacts such as 12 can be connectedtogether, in groups, by means of cross bar connectors 23. It is possiblealso to arrange these in a variety of manners, on the insulating orfixed plate 1. Alternatively, instead of cross bars 23, a printedcircuit can be used, and the corresponding switching operation is theneffected with contacts 13, which are moved by the cams 9, and which mayalso be arranged in the form of rollers.

When a printed circuit construction is adopted, the stationary contactscan be provided as a metal foil which is applied to the fixed orinsulating plate 1. At the same time insulating plate 1 is provided withapertures 15 and in general, reliable operation, even where complicatedswitching operations are concerned, is possible with minimum adjustment.

FIGURE 4 indicates an advantageous way of forming the cam followers 9.As shown, a contact spring 24, has the end turned downwardly to passthrough and be guided by the aperture 15, for example, by closeengagement against one surface 25 of the aperture. The apertures 15 canthen accordingly be of lesser size. In the position of rest, the contactspring 24 bears against the shoulder 26 of the insulating plate, and itis thus possible to provide an appropriate initial spring tension.

FIGURE 6 is a diagram indicating an alternative method of arranging thecontacts. In FIGURE 6 the insulating plate 27, on which the contactoperating bars 28 are arranged radially, or substantially tangentially,are disposed with cam followers 29 extending through apertures 30; in asimilar manner, operation of the co'operating contacts, not shown, iseffected.

By means such as those described, it is possible to provide a switchwhich, with one operating plate, can control a large number ofelectrically oscillated switching operations, to be carried out atdifferent contact positions: this is very desirable in the case of thecontrol of a complicated programme such as may be followed in theoperation of a washing machine or dish-washing machine. With theconstruction described it is a simple matter to exchange the individualinsulating discs or plates such as 1, and use discs carrying differentprinted circuits, thus affording the means of providing a variety ofprogrammes. To faciiitate dismantling, for the purposes of replacement,servicing or repair it is desirable that the contact means should bedisposed on the true upper side of the respectively fixed insulatingplate 1, and for the connections to the contacts 12 or 23 to be made bydetachable connections such as plug-type, screw-type or solderedconnections.

It is also possible for the arrangement to be such that plate 1 carryingthe cam means be fixed, while plate 1 supporting the contacts ismovable. It is also possible for both plates to be movable, one platebeing arranged to be movable through a manually adjustable angle, whilethe other plate is driven by a driving means at, for ex- 60 ample, auniform speed; the rotating plate can then be a driven by means of aperipheral toothed ring, engaged by a driving pinion. Other drivingmeans can, of course, be adopted, and another plate, running at adifferent speed, can also be disposed in the rotatable plate.

The invention can be applied generally to a variety of cases where it isdesired to effect relatively complicated switching operations by meansthat can be cheaply manufactured, while reliable operation is ensured.The invention makes this possible, without the use of complicatedcontact arrangements, by the use of the actuating bars disposed on edge,and moved in a direction parallel to the pivot axis.

I claim:

1. An apparatus for switching electric circuits comprising, a stationaryplate having a plurality of spaced contacts on one face thereof, arotary disc, means resiliently holding said disc in spaced relation tothe other face of said plate, the adjacent face of said disc havingconcentric grooves having camming surfaces therein; said stationaryplate carrying on said one face a group of resiliently actuated armshaving cam followers on the ends thereof, openings in said plateopposite the respective grooves, said cam followers projecting throughthe respective openings and into the grooves, each of said arms having acontact normally in engagement with one of said first-named contacts,said camming surface in said grooves operating to break the engagementof said contacts, and said contacts being connected to electricterminals.

2. The invention as defined in claim 1, wherein the contacts on thestationary plate are carried by metallic cross-bar connectors, and theactuating arms with contacts thereon are provided with resilientfrictional couplings.

3. The invention as defined in claim 1, wherein the contacts on thestationary plate are provided by a printed circuit section.

4. The invention as defined in claim 1, wherein spacers are providedbetween the stationary plate and disc and the disc is spring-urgedtoward the plate and against the spacers, and wherein printed circuitsections are superimposed with the actuating arms extendingtherethrough.

5. The invention as defined in claim 1, wherein electric connectionswith the contacts are made on top of the stationary plate.

References Gited in the file of this patent UNITED STATES PATENTS1,441,525 Presgraves et al Jan. 9, 1923 2,055,031 Hutchings Sept. 22,1936 2,703,347 Constantine Mar. 1, 1955 2,798,124 Shar'oaugh July 2,1957 2,842,627 Wagner July 8, 1958 2,853,563 Bole et al. Sept. 23, 19582,877,317 Euler et a1 Mar. 10, 1959 3,032,617 Holzer May 1, 19623,056,864 Albee Oct. 2, 1962 FOREIGN PATENTS 123,619 Austria July 10,1931

1. AN APPARATUS FOR SWITCHING ELECTRIC CIRCUITS COMPRISING, A STATIONARYPLATE HAVING A PLURALITY OF SPACED CONTACTS ON ONE FACE THEREOF, AROTARY DISC, MEANS RESILIENTLY HOLDING SAID DISC IN SPACED RELATION TOTHE OTHER FACE OF SAID PLATE, THE ADJACENT FACE OF SAID DISC HAVINGCONCENTRIC GROOVES HAVING CAMMING SURFACES THEREIN; SAID STATIONARYPLATE CARRYING ON SAID ONE FACE A GROUP OF RESILIENTLY ACTUATED ARMSHAVING CAM FOLLOWERS ON THE ENDS THEREOF, OPENINGS IN SAID PLATEOPPOSITE THE RESPECTIVE GROOVES, SAID CAM FOLLOWERS PROJECTING THROUGHTHE RESPECTIVE OPENINGS AND INTO THE GROOVES, EACH OF SAID ARMS HAVING ACONTACT NORMALLY IN ENGAGEMENT WITH ONE OF SAID FIRST-NAMED CONTACTS,SAID CAMMING SURFACE IN SAID GROOVES OPERATING TO BREAK THE ENGAGEMENTOF SAID CONTACTS, AND SAID CONTACTS BEING CONNECTED TO ELECTRICTERMINALS.